Spot beams satellites have become common on the Ka band and Mobile Satellite Services (MSS) bands (S band and L band). The Ka band, the L band and the S band are portions of the microwave band of the electromagnetic spectrum. The Ka band ranges from approximately 18 to 40 GHz, the L-band ranges from approximately 1 to 2 GHz, and the S-band ranges from approximately 2 to 4 GHz.
Spot beam satellites produce signals that are concentrated on a limited geographical area. Spot beams are typically used where a content provider wishes to restrict content to an intended reception area. Only receivers within the limited geographical area covered by the spot beam are able to receive the content. Spot beam satellites may be used to transmit a variety of content, such as audio and video content. For example, satellite television providers may use spot beam satellites to provide localized content to subscribers in different cities.
Due to the confined nature of the signals produced by each spot beam, spot beam satellites facilitate frequency reuse. Multiple beams from one or more satellites may use the same frequency to transmit different data without interfering with one another, so long as each beam is focused on a different geographical area. As a result, receiver design may also be simplified in spot beam systems, as the receiver does not require logic for distinguishing data received from multiple transmitters on the same frequency. For example, returning to the satellite television example described above, a satellite television provider can transmit content to localized content to different cities using the same frequency. Each city would be covered by spot beams providing localized content for that city and subscribers in each city would be able to receive the content on the same frequency. Thus, the satellite television provider could provide receivers configured to receive on the same frequency regardless of the geographical location of the subscriber.
In contrast to spot beam satellites, broadcast satellites produce a single large beam that covers a wide geographical area. Broadcast satellites are typically used to provide the same content to a large number of users distributed over vast geographical areas, such as the continental United States (CONUS). Broadcast satellites, like spot beam satellites, may be used to transmit a variety of content, such as broadcast audio and video.
A typical satellite has a functional lifetime of approximately 15 years and requires a large investment in resource in order to construct, place in orbit, and maintain the satellite. Accordingly, systems and method that enable the mission of a spot beam satellite to be changed from spot beam transmission to broadcast transmission, and vice versa, without requiring that the satellite be reconfigured are desired.